What are two major quenching routes?

Minimizing uneven heating and overheating is key to imparting desired material properties. The second step in the quenching process is soaking. Workpieces can be soaked in air (air furnace), a liquid bath, or a vacuum. The recommended time allocation in salt or lead baths is up to 6 minutes.

What is the difference between quenching and tempering?

The process of quenching or quench hardening involves heating the material and then rapidly cooling it to set the components into place as quickly as possible. Tempering is achieved by heating the quenched material to below the critical point for a set period of time, then allowing it to cool in still air.

Do you temper after quenching?

Tempering is usually performed after quenching, which is rapid cooling of the metal to put it in its hardest state. Higher tempering temperatures tend to produce a greater reduction in the hardness, sacrificing some yield strength and tensile strength for an increase in elasticity and plasticity.

Does quenching increase ductility?

After being quenched, the metal is in a very hard state, but it’s brittle. The steel is tempered to reduce some of the hardness and increase ductility.

How do you stop quenching warping?

You can also minimize warping by quenching at the slowest rate your steel allows for hardening. That is, if it’s an oil hardening steel, don’t quench it in cold oil, or water. Also minimize motion in the quench that would cool one side more than the other.

Is used motor oil good for quenching?

New and used motor oils can be used for quenching and are both widely available. New motor oil is typically cheaper to use than commercial quenching oils. Used motor oil is oftentimes free or easy to obtain, but it can contain a few contaminants from being used in a vehicle.

Can you reuse quenching oil?

Yes you can reuse it. After thousands of quenches, it will start to degrade and lose quenching speed. As for disposal, if you follow your local disposal instructions for either motor oil or cooking oil, you’ll be fine.

What is quenching a blade?

Quenching traps cementite within the ferrite and creates a very hard steel called martensite. Now that the steel is hardened, it can be tempered. Tempering, or heat treating, is done by heating the blade again. Most bladesmiths temper a blade several times to get the exact level of hardness.

What is the difference between quenching and annealing?

During the annealing process, the structure does not change, mainly to eliminate the internal stress of the metal. The steel is heated to a critical temperature above 30-50℃. Compare quenching with annealing and normalizing, the main difference is the quick cooling, the purpose is to obtain martensite.

Is annealing quenching?

In the case of ferrous metals, such as steel, annealing is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Copper, silver and brass can be either cooled slowly in air, or quickly by quenching in water.

What is Normalising steel?

Normalising involves heating a material to an elevated temperature and then allowing it to cool back to room temperature by exposing it to room temperature air after it is heated. This heating and slow cooling alters the microstructure of the metal which in turn reduces its hardness and increases its ductility.

Is Tempering same as annealing?

Annealing involves heating steel to a specified temperature and then cooling at a very slow and controlled rate, whereas tempering involves heating the metal to a precise temperature below the critical point, and is often done in air, vacuum or inert atmospheres.

What is the purpose of tempering?

Tempering, in metallurgy, process of improving the characteristics of a metal, especially steel, by heating it to a high temperature, though below the melting point, then cooling it, usually in air. The process has the effect of toughening by lessening brittleness and reducing internal stresses.

What is the purpose of quenching and tempering steel?

Quench & Tempering Steel Bar Quenching and tempering are processes that strengthen materials like steel and other iron-based alloys. These processes strengthen the alloys through heating the material while simultaneously cooling in water, oil, forced air, or gases such as nitrogen.

Why is quenched steel harder?

If the metal is quenched, however, the alloying metals are trapped within the crystal grains which makes them harder. The precipitates also reduce the movement of dislocations which contributes to the hardness of the material. Quenching is an important process that is used in the production of steel cutting tools.

What is the difference between forged and tempered steel?

To make steel harder, it must be heated to very high temperatures. However, very often, this process leaves the steel very brittle and susceptible to breaking during use. Tempering reduces the hardness of the forged steel very slightly but improves the overall product as it results in steel that is much less brittle.

What happens to steel when it goes through the tempering and quenching process?

By tempering quenched steel, it becomes less brittle and more ductile without sacrificing too much hardness. It is the combination of these two processes that produces a harder, tougher steel that’s more weldable and ductile than ordinary carbon steel.